In the paper, Romina Martin and colleagues investigate sources of variability in drought-prone pastoral systems that can threaten the livelihood security of pastoral households. They developed a model that simulates a managed grazing system driven by different scenarios of rainfall and drought. Resulting time series of livestock were than assessed regarding their ability to fulfill the income demands of a pastoral household. By mutually excluding different sources of variability, they found out that plant-herbivore dynamics dominate over the effects of drought. This means that pastoral households are more likely to become vulnerable when changing to an unfavorable mobility strategy that affects plant-herbivore dynamics than from drought effects alone.

Another paper based on the same model appeared earlier this year. There, the authors examine climate change effects on pastoralism in drylands. Both articles exemplify how general questions about pastoralism can be discussed with the support of a rule-based model that represents only a subset of the involved processes. The studies were motivated by a traditional pastoral system in Morocco.

A mixed herd with sheep and goats in the High Atlas Mountains, Morocco, 2008